Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$169.26	3.370%	$174.9641	$174.96	$174.95	$175.00
Purchase #2	$184.29	6.622%	$196.4937	$196.49	$196.50	$196.50
Purchase #3	$208.82	10.747%	$231.2619	$231.26	$231.25	$231.30
Purchase #4	$184.72	3.749%	$191.6452	$191.65	$191.65	$191.60
Purchase #5	$55.90	11.761%	$62.4744	$62.47	$62.45	$62.50
Purchase #6	$140.82	4.362%	$146.9626	$146.96	$146.95	$147.00
Purchase #7	$166.71	11.786%	$186.3584	$186.36	$186.35	$186.40
7 purchase totals =	$1,110.52		$1,190.1603	$1,190.15	$1,190.10	$1,190.30